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1. Field of the Invention
The present invention relates to footwear utilized in dance. More particularly, the present invention relates to a specially configured dance shoe arrangement that enables couples to execute lift spin dance maneuvers more easily.
2. General Background of the Invention
Athletic pursuits have long been a popular and pleasurable pastime, favored by young and old alike as an integral part of a healthy lifestyle. For the great majority of athletic activities, the single most important piece of equipment is comprised of the footwear.
Athletic footwear is currently available in a wide assortment of styles, each specifically adapted for a particular use and ranging from lightweight, high traction running shoes to rigid, protective ski boots. More practical footwear is also available in many choices, from comfortable shoes for walking over extended periods of time to heavily insulated and reinforced work boots. Some articles of footwear are designed to facilitate a variety of activities such as running, walking, jumping and skateboarding. Other articles of footwear are designed specifically for a certain activity, such as dance shoes.
Dance shoes are designed to allow the wearer to execute spinning, sliding or gliding maneuvers on or across the dance floor. The soles and heels of dance shoes are made of materials providing low coefficients of friction.
Various inventors have developed various devices to enable one to engage in activity that enables the wearer to slide or spin. One such device is built from a low friction material and attached to the sole of the shoe in the arch region, thereby allowing the user to slide across a smooth flat surface such as a dance floor. The device may extend below the heel of the shoe and leaves the forefoot area exposed so that the user may engage the floor with the sole to be able to push off into a sliding maneuver. A device of this type is disclosed in U.S. Pat. No. 2,572,671.
Another shoe design that has been patented incorporates a low friction region protruding centrally from the sole with high friction areas surrounding this protuberance. The user can thus engage the supporting surface by tilting the foot to lower the high friction areas of the sole and can slide by pushing off and balance on the protruding area. U.S. Pat. No. 1,984,989 discloses a device of this type.
These prior devices are designed for use on flat, smooth surfaces by a single individual (the wearer). No known prior device lends itself to the execution of two dancers spinning as a single unit (hereinafter, referred to as a coalescent-spinning or xe2x80x9clift spinxe2x80x9d dancing). Thus, although well adapted for their intended use as dance footwear, these devices are of limited usefulness and are not the ideal solution for persons desiring to engage in coalescent-spinning activities.
Another shoe design that has been patented incorporates low friction surfaces for sliding across a protruding feature on a supporting surface and walking surfaces for other athletic pursuits, and a method of making same. These shoes have longitudinal grind plates built into the bottom and sides of the shoe to allow the wearer to duplicate maneuvers done with skateboards called grinding. U.S. Pat. No. 6,158,150 discloses an item of this type. These shoes are not intended for dancing, spinning or coalescent-spinning activities.
All of the U.S. Patents mentioned herein are incorporated herein by reference.
The apparatus of the present invention facilitates performing the acrobatic maneuvers called coalescent-spinning or lift spin dancing by enabling a person wearing the shoes to engage an angled or inclined surface (or protruding member) on a supporting surface and support the entire weight of their dance partner while spinning. A unit of low friction surface formed on the shoes can be provided in selected configurations. The low friction spinning surfaces of the present invention can be formed integral to the shoes or can be attached thereto as removable spinning elements, and are equally adaptable to athletic, work, or recreational footwear of all types and styles.
In one embodiment the spinning surfaces of the present invention do not interfere with the traditional functions of footwear and do not require the user to adjust her normal walking, running or dance gait when wearing shoes equipped with such spinning surfaces. Another embodiment includes the incorporation of a liner (e.g., Sorbothane(copyright)) or other bruise-protection material within the shoe to protect the wearer""s feet from forces exerted by their partner""s weight. In another embodiment the apparatus of the present invention adapts specialized equipment to traditional footwear and thereby enlarges the usefulness of such footwear and the enjoyment level of persons wearing it.
The present invention can also be implemented in a wide range of aesthetic and practical choices for design and manufacturing, and can be adapted to appeal to diverse markets and consumers. The coalescent-spinning or lift spin dance apparatus of the present invention can be characterized by a shoe having a heel with a section angled upwardly (away from the floor) at the rear of the heel. This angled section of the heel can be referred to as the coalescent surface. The coalescent surface can be flat and sloped for example between 30 and 60 degrees, more preferably between about 35 and 45 degrees, and even more preferably between about 40 and 45 degrees, measured from the bottom surface of the heel. The coalescent surface can be covered by or comprised of the same low coefficient of friction materials as that of the rest of the heel. A shoe configured in this manner can be called a coalescent dance shoe. The heel by itself is called a coalescent heel. Any make or style of shoe can be made into a coalescent dance Shoe by replacing or installing a coalescent heel as described herein to the bottom of the shoe. The coalescent dance shoe operates in the same manner for either the left or right foot.
A pair of coalescent dance shoes offers a dance couple a wide range of new spinning and acrobatic maneuvers. When a dancer wants to use the coalescent-spinning feature of the coalescent dance shoes, they lift the front of their foot until the coalescent surface is in contact with the dance floor. The partner then leaps, steps or leans on top of the dancer""s foot with both spinning as a single unit. This apparatus provides the capability to perform coalescent-spinning maneuvers without hampering the user""s ability to perform other traditional dancing activities or individual maneuvers.
Another embodiment of the aforementioned apparatus is one containing a projection within the coalescent surface. A shoe with this design is called a low-friction coalescent dance shoe. A heel by itself and of this design can be called a low-friction coalescent heel. The spinning point or projection can be comprised of low coefficient of friction material that is slightly raised above the surface of the heel""s inclined surface or coalescent surface. The raised point will reduce the effective surface area in contact with the floor and increase spin speeds. The spinning point can have many different shapes and designs providing a wide range of handling characteristics.
The present invention includes a dance shoe, that is, a shoe adapted in design and manufacture for activities involving all forms and types of dance.
Because the design of some embodiments places all coalescent-spinning elements outside of the shoe interior, additional cushioning material may be placed over the insole to increase the user""s comfort and safety during coalescent-spinning maneuvers.
In another embodiment the apparatus can be mounted onto any type or model of dance shoe making the shoe a coalescent dance shoe. The coalescent heel may be formed with different downward facing configurations, and thus a coalescent heel adapted for dance floors with higher coefficients of friction may feature a high degree of angle and narrower coalescent surface, whereas a coalescent heel for faster dance floors may feature a lower degree of angle and wider coalescent surface. In addition, coalescent heel may be manufactured in different colors that appeal to the fashion sense of the user, and individual coalescent surface may be formed with strata of different colors to indicate the degree of angle or even the level of wear upon the coalescent surface.
The present invention is not limited to providing coalescent-spinning elements that are permanently attached to articles of footwear. Any method may be used to provide an article of footwear with low friction coalescent-spinning surfaces, and may include forming the spinning surfaces integral to the sole and/or heel during the extrusion molding process, or alternatively may consist of sintering low friction material into certain regions of the sole and/or heel. The use of such permanent, non-removable spinning surfaces is highly dependent upon the ready availability of materials of sufficient durability to withstand repeated coalescent-spinning activities on dance surfaces for the expected lifetime of the article of footwear. In another embodiment the present invention can also include removable coalescent-spinning elements.
The present invention is not limited to providing coalescent-spinning surfaces on the rear of the heel of an article of footwear. Low friction coalescent-spinning surfaces may also be formed on the sides of the heel or the corners of the heel.
In operation, when a user desires to participate in dancing activities, he or she may put on the shoe and can dance in the normal fashion. The coalescent surface can be sufficiently recessed upwardly from the bottom surface of the heel to reduce contact with the supporting surface. Thus, the present invention allows the sole of the shoe to function along the supporting surface in the manner typical to most footwear and does not force the user to change his or her normal dance gait.
Because the normal dance gait of an upright human involves first contacting the heel of the shoe and then rolling forwardly onto the ball of the foot and then lifting the heel up, most of the flex in the sole is localized in the forward and metatarsal area of the foot with more rigidity being in the arch. During coalescent-spinning activities, the bulk of the user""s foot control is shifted from the central arch section to the back heel section. To facilitate this control, additional rigidity in the foot frame may be required in the aft-foot section for certain types of dance shoe.
The present invention is comprised of a dance shoe, that is, a shoe adapted in design and manufacture for activities involving all forms and types of dance. The low-friction coalescent dance shoe is similar in all respects with the coalescent dance shoe except it has an additional feature of a spinning point added to the coalescent surface. The spinning point will have many different shapes and designs providing a wide range of handling characteristics. In addition, because the spinning points are removable and relatively compact the user may conveniently carry one or more of them in a bag or even in a coat or pant pocket and interchange them as the coalescent-spinning conditions encountered may warrant, thereby increasing the range of coalescent-spinning options and opportunities.
Because the design of the present embodiment places all coalescent-spinning elements outside of the shoe interior, additional cushioning material may be placed over the insole to increase the user""s comfort and safety during coalescent-spinning maneuvers.
Although the embodiments described herein have been described in terms of spinning surfaces or elements formed or adapted to shoes, it will be appreciated by those skilled in the art that the apparatus of the present invention is equally adaptable to any and all types of footwear. Coalescent-spinning surfaces can thus be formed in elements adapted to, sandals, boots, shoes, slippers and any other device or article of wear that is meant to be attached to the human foot. This apparatus can be mounted onto any type or model of dance shoe making the shoe a coalescent dance shoe.
The low-friction coalescent heel may be formed with different downward facing configurations. Thus a low-friction coalescent heel adapted for dance floors with higher coefficients of friction may feature a high degree of angle and narrower coalescent surface and spinning point, whereas a low-friction coalescent heel for faster dance floors may feature a lower degree of angle and wider coalescent surface and spinning point. In addition, a low-friction coalescent heel may be manufactured in different colors that appeal to the fashion sense of the user, and individual coalescent Surface and spin points may be formed with strata of different colors to indicate the degree of angle or even the level of wear upon the coalescent Surface.
The low-friction coalescent heel may be attached to the sole of any type shoe by any means of sufficient mechanical strength to withstand the shear forces generated during coalescent-spinning maneuvers, such as chemical bonding. Alternatively, the coalescent surface may be configured with ribs or other protuberances that reduce total spinning area and thus total frictional resistance. And, the spin point may be formed from any low friction material exhibiting sufficient stiffness and mechanical strength to be directly attached to the low-friction coalescent heel.
In operation, when a user desires to participate in dancing activities, he or she may put on the shoe and can dance in the normal fashion. The coalescent surface and spinning point are sufficiently recessed upwardly from the bottom surface of the heel to reduce contact with the supporting surface. Thus, the present invention allows the sole of the shoe to function along the supporting surface in the manner typical to most footwear and does not force the user to change his or her normal dance gait.
Because the normal dance gait of an upright human involves first contacting the heel of the shoe and then rolling forwardly onto the ball of the foot and then lifting the heel up, most of the flex in the sole is localized in the forward and metatarsal area of the foot with more rigidity being in the arch. During coalescent-spinning activities, the bulk of the user""s foot control is shifted from the central arch section to the back heel section. To facilitate this control, additional rigidity in the foot frame may be required in the aft-foot section for certain types of dance shoe.
The spinning point can be constructed of a material selected to afford the desired low coefficient of friction spinning characteristic. In addition, the material selected must offer substantial rigidity when cut, injection molded or shaped in the dimensions specified to allow the user to maintain control while engaged in coalescent-spinning maneuvers. A material known to exhibit these desirable characteristics is Supertuf 801 Nylon available from Dupont. Other materials that may be found to be acceptable include other forms of nylon, such as Nylon 6, plastics such as PTEX, ceramics, metals, polyethylene and composites.
The spinning point is selected and installed on or inserted within the cavity of the low-friction coalescent heel, where it is secured by threading a screw through the spinning point and into the core heel material or an anchor made of brass, stainless steel or other materials. The screw is conveniently provided with engagement slots or sockets formed in the top surface of the heads for engagement by a screwdriver or other tool for quick and easy turning. Alternatively, or in addition, high strength adhesives such as epoxy may be employed to fasten the spinning point to the coalescent surface in a permanent configuration that sacrifices spinning point interchangeability for a stronger, more secure bond. The spinning point can be manufactured in a variety of styles to fit a variety of uses, and the rapid replacement feature detailed above enables quick swapping of spinning points to accommodate varying conditions and surfaces. In this manner a user may choose, for example, to install one type of spinning point on the right shoe and a different type of spinning point on the left shoe.
As described earlier, spinning points may be formed in many different materials, colors, sizes, and bottom configurations, and the design of the present embodiment allows the user to quickly and easily change spinning points at any time he or she may choose to do so. As mentioned above, the fasteners are preferably self-locking screws, thereby reducing the likelihood that the vibrations and shocks experienced by the shoes during use will loosen and eventually eject the screws.
The screw can be, for example, a Nylock self-locking screw of 4 or 5 mm shaft diameter, approximately 12 mm head diameter, and varying length as dictated by the overall height of the spinning point. Screws of various lengths and or materials such as elastomers may be used to accommodate different spinning point materials and thickness, giving the user the ability to adjust performance characteristics of the spinning point to match the requirements of different dancing surfaces.
The removable spinning points require some rudimentary tools, whether a screwdriver, a knife, or a coin, to disengage the respective fasteners and remove the spinning point. It is foreseeable that the need may arise for a spinning point design employing a fastening system that requires absolutely no tools for removal and replacement, and is even quicker and easier to operate.
When a couple executes a lift spin or coalescent spin, the dancer having contact with the dance floor (first dancer) is considered the spinner and the dancer with no contact with the dance floor (second dancer) is considered the rider. The rider can use any part of their body on that of the spinner""s body to remove contact with the dance floor.
A highly athletic activity involving, for instance, an aggressive foot-on-foot coalescent-spinning maneuver wherein the rider might step with some force onto the top surface of the spinner""s foot, the landing force of the rider may exceed the weight of the athlete, e.g., 100 pound (45 kilogram) rider lands with, e.g., 110 pounds (490 newtons) of force. Sufficient structural integrity to withstand such impacts can be built into the interior and exterior portions of the shoe (e.g., Sorbothane(copyright)) providing for cushioning of the top, sides and heel portions of the spinner""s foot thereby minimize bruising and injury.
As the spinner maneuvers in a coalescent-spinning action, he or she can maneuver the foot about to maintain control or execute further acrobatic maneuvers. When the spinner elects to undertake a maneuver requiring a crouch position, he or she may bend the knees into a deep bend without losing contact with the coalescent surface.
This apparatus can be mounted onto any type or model of dance shoe making the shoe a coalescent dance shoe. The rear of the heel comprises the coalescent surface and is attached and held firmly to the main heel body through the use of a grooved channel and two magnets. The magnetic force is exerted on two metal slots recessed and adhesively bonded in to the main heel body. The detachable portion of the heel allows the user to quickly change the function of a shoe depending on which style of attachment is used. In this way, a coalescent dance shoe can be converted into a low-friction coalescent dance shoe or can even be made to look like a generic model shoe.
A coalescent surface attachment can be inserted into a groove at the rear of the heel and once attached and held firmly to the shoe through use of rivets, screws, adhesive and/or any other means of fastening.
A ball bearing mounted projection can be recessed into the main heel body, but sufficiently exposed above the coalescent surface to allow contact with the surface of the dance floor when the user enters into a coalescent spin with their partner. The ball bearings can be made of a low-friction polymer such as Teflon, but can be made of just about any material depending on its usefulness, availability, and non-deleterious effects on dance surfaces. The number of ball bearings used can vary from one to many.
A spinning disk can be recessed into the main heel body, but the surface of the spinning disk is sufficiently exposed above the coalescent surface to allow contact with the surface of the dance floor when the user enters into a coalescent spin with their partner. The surface of the spinning disk will be covered with the same materials used on the coalescent surface, but any other materials can also be used depending on the user""s preferences. The internal mechanism of the spinning disk utilizes an axle and roller bearing configuration similar to those used in most bicycle wheels. The size and configuration of the spinning disk used can vary.
A low-friction spinning point is fastened to the main heel body and is surrounded by a compressible medium such as Sorbothane. The thickness of the compressible medium has equal height dimensions as that of the low-friction spinning point. The same material used to cover the bottom of the heel (the portion in normal contact with the dance floor) is also used to cover the compressible medium. However, this covering material does not cover or interfere with the top of the low-friction spinning point. The durometer of the compressible medium will be such that the weight of the wearer alone does not compress the medium enough to expose the surface of the low-friction spinning point to the dance floor, but the addition of their partner""s weight (50 pound (222 newton) minimal differential) will be sufficient enough weight to compress the medium enough to expose the surface of the low-friction spinning point to the dance floor.
The sole and heel are independent of each other. When this type sole is mounted to the bottom of a dance shoe, it allows the wear to execute spins on the low-friction spinning point by placing all of their weight onto the ball of the foot, which compresses the medium and exposes the low-friction spinning point. The durometer of the compressible medium will be of sufficient hardness to allow a dancer to perform normal dance activities without exposing the low-friction spinning point, but of sufficient softness to allow maximum compressibility when subjected to the full weight of the dancer. While the dimensions and core materials of the sole are different than the heel, a heel of this type design operates in the exact same way as that of the sole outlined above.
When the wearer of a shoe rocks back to execute a spin with their partner, their combined weight can be used to activate a system where one or more low-friction spinning points are pushed from the bottom of the heel to aid in maintaining balance. The pressure system can be of various designs, but is anticipated to use a non-compressible liquid medium housed in a rubber bladder. The pressure system can also be located in various sections of the shoe depending on the desired performance requirements.
When the wearer of a shoe with this style of heel rocks back to execute a coalescent spin with their partner, the partner""s weight activates a system where the front portion of the heel is released from the shoe body and pivots down to make contact with the dance floor automatically latching in that position. Once the partner removes their weight, the latch is released allowing the wearer to rock forward and automatically lock the heel in its normal position. The activation system can be of various designs, but is anticipated to use a battery-powered sensing and operating mechanism housed within the upper portion of the shoe and heel body.
The front bottom of the heel (portion facing the inner arch of the foot) can be angled upwards away from the dance floor with an angle of between about 10 and 80 degrees, but normally expected to be about 45 degrees. Adhered to the face of the angled portion of the heel can be a layer of absorbent material such as Sorbothane. When the rider of a coalescent spinning couple steps onto the spinner""s foot, the absorbent material of the rider""s heel becomes one of the load bearing points. The absorbent material prevents bruising of the spinner""s foot. The durometer of the absorbent material can be varied according to the dancer""s requirements, but is expected to normally be of 60 durometer.
Other features and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features of the invention. While each of the figures that accompany the disclosure depicts an article of footwear being used on the right foot of a user, every embodiment disclosed herein can be equally adaptable to use on the left foot of a user.